Organization of the Nervous System

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Organization of the Nervous System
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I. Nervous System
A. Central Nervous System (CNS)

• Brain and spinal cord

B. Peripheral Nervous System (PNS)

• Ganglia and peripheral nerves

1. Somatic

• sensory neurons

• somatic motor neurons (skeletal)

2. Autonomic

• motor neurons viscera,smooth,glands

• Sympathetic Parasympathetic

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Central Nervous System
I. Seven regions

• Spinal cord, Medulla Oblongata, Pons, Midbrain,
  Diencephalon, Cerebrum, Cerebellum

A. Spinal Cord
1. Sensory inf.
2. Contains motor neurons
3. Spinal nerves

• Posterior (Dorsal) root

• Anterior (Ventral) root

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B. Medulla Oblongata
1. Pathway for nerve tracts
2. Reflex center

• Respiration, heart rate, swallowing, etc.

• Respiration 2 groups of neurons (nuclei)

Dorsal group
ventral group
Receives afferent info signal to
respiratory Motor neuron
C. Pons
1. Relays info from cerebrum to
cerebellum
2. Respiration
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D. Midbrain
1. Visual system
2. Auditory system
3. Motor activity
E. Reticular formation
1. Alertness
F. Diencephalon
1. Thalamus

• process distributes sensory and motor inf to
  cortex

2. Hypothalamus

• controls basic drives/autonomic
  response/emotions

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G. Cerebrum
1. Three layers

• cerebral cortex (top)

• white matter

• deep-lying nuclei

2. Lobes

• Frontal

• Parietal

• Occipital

• Temporal

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3. Cortex

• Olfactory cortex

• Primary somatic sensory cortex

• Visual cortex

• Auditory cortex

4. Language area

• Wernickes area understand and formulate
  speech

• Brocas area movements for speech

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5. Memory
a. Types

• Declaration

• Procedural

b. Areas

• Hippocampus

• Amygdaloid nucleus

• Cerebellum/premotor of cerebrum -Procedural

c. Stages of memory

• Short term

• Long term (intermediate vs full)

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d. Long term memory

• presynaptic neuron in hippocampus releases
  Glutamate

• binds to 2 different receptors in Postsynaptic
  cell

Q/K receptor ligand gated NaK channel
NMDA receptor ligand
voltage gated Na/K/Ca
voltage change due to many Q/K opening

• Ca enters activates Calmodulin kinase
  protein kinase C

• produces Nitric oxide (retrograde)

• NO enters presyn. Terminals to enhance
  glutamate release

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H. Cerebellum

• somatosensory input from spinal cord

• motor input cerebral cortex

• balance inf from inner ear

• coordinates muscle movement

• balance and muscle tone

II. Nerve Pathways

A. Dorsal column/medial lemniscal system

• axon of primary neuron moves up dorsal column

• synapses w/2nd neuron at medulla

• axon decusses to opposite side

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• 2nd synapses w/3rd at Thalamus

• release of neurotransmitter at somatic sensory
  cortex

B. Corticospinal

• axons of motor neurons -gt medulla

• 85 cross over descend to spinal cord

• remaining 15 cross at the spinal cord

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